<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
<script>
function fun(str){
    console.log(str);
    var str ='123';
    function str(){
        return '999';
    }
}
fun('456');


function fun1(str1){
    function str1(){
        return '2';
    }
    var str1='3';
    console.log(str1);
}
fun1('1');
</script>
</body>
</html>